Michael Thomas, chairman of the Mashantucket Pequot Tribal Nation in Connecticut, left, makes remarks as Gov. Ed Rendell listens during a news conference at City Hall in Philadelphia.

NEW HAVEN, Conn. — A former chairman of the Indian tribe that owns the Foxwoods Resort Casino improperly charged $80,000 to a tribe-issued credit card for a limousine to shuttle his mother to doctor’s appointments, a prosecutor said Monday at the opening of a federal theft trial.

Michael Thomas, who led the Mashantucket Pequot Tribal Nation from 2003 to 2009, was in financial distress when he used the card for personal expenses totaling more than $100,000, prosecutor Christopher Mattei said in his opening statement. He said the credit card was supposed to be used only for business purposes under a tribal resolution that Thomas signed.

The riches from the tribe’s casino once made its tiny reservation in southeastern Connecticut one of the wealthiest communities in the United States. The charges in question were made on a tribe-issued American Express card between 2007 and 2009, when the tribe entered a new period of austerity as the casino began to struggle with the effects of the recession and increased competition in nearby states.

A defense attorney, Paul Thomas, said the jury will have to decide whether the credit card charges really were disallowed.

“Was it impermissible to charge travel on behalf of his sick, dying mother to get treatment?” said Thomas, who is not related to his client.

Michael Thomas has pleaded not guilty to one count of theft from an Indian tribal organization and two counts of theft concerning an Indian tribal government receiving federal funds.

He was indicted in January along with his brother, tribal treasurer Steven Thomas. The brother, who is being tried separately, has pleaded not guilty to charges that he stole more than $700,000 from 2005 to 2008 when he was assistant director of the tribe’s natural resources department.

Mattei said the personal charges Michael Thomas made to the card included expenses for Direct TV and satellite radio service in his Cadillac Escalade. He said Thomas did not submit monthly expenses as required.

One of the first witnesses was Barbara Poirier, the tribe’s director of health services, who testified that the tribe has transportation services available for members who need to travel for medical appointments.

Thomas’ credit card use was discussed within the tribe’s finance department, said Laura Sasser-Cuff, a former employee

“I escalated it to my direct supervisor,” she said.

One of Thomas’ charges was at Victoria’s Secret, Sasser-Cuff said. She also testified there were tribal layoffs during the period when Thomas was making such charges.

Jeffrey Wosencroft, Thomas’ former chief of staff and a longtime friend, said Thomas was very busy, traveling extensively and working on a $1 billion deal involving MGM.